The structural origin of β-relaxation is still an open issue in glassy materials. Focusing on the as-cast and annealed La₅₀Al₁₅Ni₃₅ metallic glasses (MGs), we demonstrate that the local vibration of Ni atoms contributes more to the β-relaxation in both samples through synchrotron X-ray measurements and theoretical calculations. It is found that besides the free volume decreases, the chemical constitution around mobile Ni atoms in Ni-centered polyhedra tends to transform from Al-free to Al/Ni-containing after annealing, which suppress the local vibration of central Ni atoms, thus leading to the unpronounced β-relaxation event. Moreover, we observe that the atomic mobility of Ni atoms more depends on their local polyhedral geometry and chemical constitution than the content of surrounding free volume. Our work paves a way to better understand the origin of β-relaxation in MGs and other glassy materials from their local atomic environments.

β-弛豫的结构起源在玻璃材料中仍然是一个悬而未决的问题。关注铸态和退火态的 La ₅₀ Al ₁₅ Ni ₃₅金属玻璃 (MGs)，我们通过同步加速器 X 射线测量和理论计算证明 Ni 原子的局部振动对两个样品中的β弛豫贡献更大。发现除了自由体积减小外，Ni 中心多面体中移动 Ni 原子周围的化学结构在退火后趋向于从无 Al 向含 Al/Ni 转变，抑制了中心 Ni 原子的局部振动，从而导致到未发音的β- 放松事件。此外，我们观察到 Ni 原子的原子迁移率更多地取决于它们的局部多面体几何形状和化学组成，而不是周围自由体积的含量。我们的工作为更好地理解MGs 和其他玻璃材料中β弛豫的起源铺平了道路。